I seem to have moles under my garden. There are small molehills popping up in the grass - I'm not that bothered as it's definitely grass rather than "lawn" but it means there are probably moles under my raised bed too. Aside from the unsightly hummocks do moles actually do damage? There's a bit online about moles damaging shallow foundations but how much of an issue is it really? How fast do they breed and will the babies all stick around? Essentially, do I need to do something about this or can I just flatten the hills when I'm walking about?